zxcvbob wrote:

Some unscrupulous company is selling... I think it's sodium carbonate; under
then brand name "TSP".

I think you're talking about "TSP substitute". I don't think TSP
substitute is sodium carbonate (washing soda). I think it's sodium
metasilicate. Big difference.

It is my understanding that sodium metasilicate is a slightly less
effective cleaner, BUT it rinses off more easily leaving no residue to
interfere with paint adhesion. Can anyone confirm/refute this?